Among the conventional methods for manufacturing stator cores for rotary electric machines, there is a first method by which a cylindrical core is manufactured by punching out annular sheet cores by press work and laminating these sheet cores.
This first manufacturing method by which the annular sheet cores are punched out by the press work produces waste portions inside and outside of the sheet cores, thereby lowering yield.
A second manufacturing method, which improves the yield, is illustrated in FIGS. 20(a) through 20(d).
According to the second method, a core division sheet 1 which has an engaging concavity 1a and an engaging convexity 1b as shown in FIG. 20(a) is first punched out by press work. A core segment 2 is composed by laminating such core division sheets 1 as shown in FIG. 20(b), the engaging convexity 1b of the core segment 2 is positioned to against one end of the engaging concavity 1a of an adjacent core segment 2 as shown in FIG. 20(c) and the convexity 1b is slid or inserted into the concavity 1a for coupling the core segments 2, thereby forming a cylindrical stator core 3 as shown in FIG. 20(d).